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W. DRR. PRESSURE GAGE.

No. 542,631. Patented July 16, 1895...

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' W. DRR.

PRESSURE GAGE.

No. 542,631. Patented July 16, 18915.

UNITED STATES PATENT OFFICE..

VALTHER DRR, OF MUN IGH, GERMANY.

PRESSURE-GAGE'.

SPECIFICATION forming part of Letters Patent No. 542,631, dated Tilly 16, 1895.

Application inea November 5,1394. serai No. 527,958. (No model.) Patented in Belgium December S1, 1887, Nm 88,838; in Switzerland December 13, 1889l No. 1,706 i in England December 14, 1889, No. 20,139,I in Austria-Hungary April 2, 1890, 170.153,572 and No. 12,103l and in' Germany June 5.1890,No. 52,318.

as will enable oth ers skilled in the art to which it appertains to make and use the same.'

My invention relates to improvements in pressure-gages.

The object of my invention is to produce a device specially adapted for use in connection with a tension air-pyrom eter or as adraftmeter for measuring'the dierence in pressure existing in chimneys, flues, and the like.

The invention consists in such features, details of construction, and combination of parts as will first be described in connection with the accompanying drawings, and then particularly pointed out in the claims.

In the drawings, Figure 1 is a front view of a device embodying my invention with the dial removed. Fig. 2 is a detail view of the same, partially in section. Fig. 3 is a horizontal section on the line 3 3, Fig. l.

Referring to the drawings, A is a casing,A lwithin the lower portion of which may be ed an oscillating receiver or bell B, which may be held from the casing A in any suitable manner to permit oscillation, as, for instance, by a leaf-spring Z, which is secured to one side of the bell and to the top of the casing, whereby the bell may swing or oscillate,

as desired, for a purpose hereinafter set forth. The bell is counterweighted by a weight Z adjustably secured bya screwsl to a stem b2 projecting from the bell. In order to retain the said bell in a particular normal or Zero position, a spring w is provided, being in this case a spiral spring secured at one end to the shaft and at the other end to the casing. To one side of the bell is attached a lever o by means of a linkvy, the other end of said lever being tixed to a spindle or shaft n, revo'lubly mounted in a bracket-arm 'n' and provided with a toothed sector s, which engages with a pinion o fixed on a spindle fvzjonrnaled in the bracket N which supports the bracket-arm n and is carried from the casingA in any suitable manner. To the spindle o2 is fixed an indexfnger or pointers', which is arranged to move over a suitable dial, (not shown,) as will be fully understood by those skilled in the art. The lower end of the inlet-pipe b is provided with a cock C, to which is connected asmall pipef, which is putin connection with the receptacle containing the air or gas whose tension is to be gaged, being shown in Fig. l as connected to an air-pyrometer K, of porcelain or other refractory material. To the pipef is also connected a tube d, provided with a mouthpiece, a cock ot being interposed between said tube and pipe.

To the top of the casing is attached a small cock b, which serves to open or close communication between the interior of the casing A and the flexible tuben e, also provided with a mouthpiece.

A compensator, consisting of a U-shaped tube r, is secured to the interior of the casing, being provided with a glass bulb at one end and a tine orifice at the other, said compensator also having at its bend a small quantity of sealing-liquid, such as mercury or parafneoil, and being provided with a zero-line or normal-mark m, which indicates the point to which the sealing-liquid will rise when the casing of the gage contains air of the same 9 IOO sion is to be measured-as, for instance, with the air-pyrometer K-the Valve C is opened, thereby establishing communication between the air to be measured and the air in the bell B, whereby both bodies of air soon arrive at the same tension. The air contained under the bell, being prevented from escaping into the casing by the sealing-liquid into .which the lower end of the bell projects, acts to force the bell upward if the tension of said conliined air is greater than that ot' the air in the casing, or if less permits the bell to fall, the amount of rise or fall of the bell being proportional to the tension of the conlined air. As the bell is capable of oscillating, it moves the lever u and thereby operates the segment S and pinion o, thus moving the pointer vz over the dial. In my construction the bell oscillates-that is to say, swings-about a fixed point or center, thus being partly supported, so that the air confined within the bell does not have to raise the entire weight of said bell, but only a portion ot' it, the remainder being carried by the support. Therefore the instrument may be operated by very slight diiterences in pressure between the air confined within the bell and that exterior to it, which is not the casein the previous constructions of which I have any knowledge, wherein it is necessary that the difference in tension between the air within the bell and thatexterior to it be great enough to lit't the entire weight of the bell.

In case the temperature of the air in vthe casing above and around the bell is not the same as that at which the 'gage was originally set the tension in said air would be altered, and hence the diierence between the amount of movement of the bell and what it would be it' the said air were at its original tension would constitute an error in the record ot` the pointer. Whenl such an error exists, it is shown by the compensator, the liquid in which Will not stand at its zero-line m. In such case it becomes necessary to establish a proper tension in said air in the casing, which is done by opening the cock b and either blowing into the tube e or sucking the air vtherefrom until the liquid in the compensator is again level with the zero-mark, whereupon the cock b may be closed and the indication of the pointer Z on the dial read off. This reading will be the true one, properly compensated. Vhen the reading of the dial has been taken, the cock l) is opened, and after the pointer has ceased vibrating the cock 0L is opened to relieve the pressure under the bell, the cock C linally being closed.

Having thus fully described my invention, what I claim as new, and desire to secure -by Letters Patent, is-

1. In a pressure-gage, the combination, with a receptacle containing a sealing liquid, and a bellinverted over said receiver and dipping therein, of means for compelling the bell to move in the arc of a circle when operating, and an indicating device actuated by the bell, substantially as set forth.

2. In a pressure-gage, a receiver containing a sealing liquid, a bell inverted over and dipping into the sealing liquid,and means for indicating the movements of the bell, in combination with a compensator, consisting in a U-shaped tube provided with a globe or enlargement ,on one arm ot' the tube, a sealing liquid confining atmospheric air in the globe. and a mark :for indicating the normal level of the sealing liquid on the other arm of the tube, substantially as set forth.

3. In a pressure-gage, the combination, with a receptacle containing a sealing liquid, and a bell inverted oversaid receiver and dipping therein, of means `for compelling the bell to move in the arc of a circle when operating, an inlet-pipe opening below the bell, and an indi-eating` device actuated by 'the bell, substantially as set forth.

4. In a pressure-gage, the combination, with a casing containing a sealing liquid, ot' a receiver openl at its lower end and dipping into the sealingv liquid, a compensating' device in communication with the interior of the casing outside the receiver, and means for varying the pressure in that part of the casing` with which the compensator communicates, substantially as set l'orth.

5. In a pressure-gage, the combination, with a casing containing a sealing liquid, of a receiver open at its lower end and dippinginto the liquid, a leaf spring from which the receiver is suspended, a lever attached to the receiver at one end, a spindle secured to the lever at the other end, a toothed segment secured to the spindle, a gear pinion in mesh with the segment, and an indicator operated by the gear pinion, substantially as set forth.

In testimony whereof I affix my signature in presence ot' two witnesses.

IVALTHER DURR. Witnesses:

EMIL HENZEL, G. DEDREUX. 

